There are basically two types of digital radio receivers. One type uses digital signal processing (DSP). This type samples one of the intermediate frequencies or the demodulated audio frequency using an A/D converter. The digital information is then processed to perform demodulation or make decisions on where the zero crossings are thus determining the 1s and 0s of the digital information. The other type of digital radio receiver must demodulate the received radio signal and produce an audio signal. That audio signal does not have sharp transitions and it is often noisy. A bit slicer must then sharpen the edges. The output of the bit slicer is then presented to a microprocessor as digital information. The task of the bit slicer is that it must determine where the zero crossings occur. Often the audio is a low amplitude sine wave riding on top of a large dc voltage. Comparators are used to perform bit slicing. If one of the inputs to the comparator (the filtered input) is biased at a dc voltage halfway between the extreme peaks of the sine wave signal, then each time that the sine wave signal crosses that voltage the output state of the comparator changes, thus converting the sine wave into a digital signal with sharp edges. The problem with this is that the large dc voltage upon which the low amplitude sine wave rides drifts with time and temperature and it is difficult to predict its value. Further, it usually takes a long time after power is applied for that dc voltage to settle. During that time the low amplitude sine wave is riding on a dc voltage which is constantly drifting, as it settles to its final value. This presents a problem for low power consumption receivers which must start receiving immediately upon power up in order to minimize the on time of the receiver.